Surface Area of Prisms
The surface area of a 3D shape is the total area of all its faces. For prisms, we find the area of each face and add them together. Surface area is measured in square units (cm^2, m^2).
What You Need to Know
Key Concept Diagram
Surface area = sum of the areas of all faces of a 3D solid
A rectangular prism (cuboid) has 6 rectangular faces in 3 pairs: SA = 2(lw + lh + wh)
A triangular prism has 2 triangular faces and 3 rectangular faces
A cube has 6 identical square faces: SA = 6 x side^2
Net: a 2D unfolding of a 3D shape that shows all faces; helps visualise surface area
Key Vocabulary
Surface Area
The total area of all the faces (flat surfaces) of a 3D solid, measured in square units
Prism
A 3D solid with two identical parallel faces (bases) and rectangular side faces
Net
A flat 2D pattern that can be folded to form a 3D shape; shows all faces
Face
A flat surface of a 3D solid
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
What is the surface area of a cube with side length 4 cm?
Question 2
A rectangular prism has length 5 cm, width 3 cm, height 2 cm. What is its surface area?
Question 3
Why is surface area important in real life?
Key Concepts Summary
- ●Surface area = sum of the areas of all faces of a 3D solid
- ●A rectangular prism (cuboid) has 6 rectangular faces in 3 pairs: SA = 2(lw + lh + wh)
- ●A triangular prism has 2 triangular faces and 3 rectangular faces
- ●A cube has 6 identical square faces: SA = 6 x side^2
- ●Net: a 2D unfolding of a 3D shape that shows all faces; helps visualise surface area